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by hn_throwaway_99 1115 days ago
Completely disagree. The issue is not about really about how hard or easy it is to run migrations (every project I've worked on has also used migration files), it's that, depending on the data, it can just be a total waste of time.

Sibling comment, "is when you want to store/use additional payment processor details for a transaction", is a great example IMO. I've dealt with card processing systems where the card transaction data can be reams of JSON. Now, to be clear, there are a lot of subfields here that are important that I do pull out as columns, but a lot of them are just extra custom metadata specific to the card network. When I'm syncing data from another API, it's awesome that I can just dump the whole JSON blob in a single field, and then pull out the columns that I need. Even more importantly, by sticking the API object blob in a single field, unchanged, it guarantees that I have the full set of data from the API. If I only had individual columns, I'd be losing that audit trail of the API results, and if, for example, the processor added some fields later, I wouldn't be able to store them without updating my DB, too.

Before JSON columns were really standard, saw lots of cases where people would pull down external APIs into something like mongo, then sync that to a relational DB. Tons of overhead for a worse solution where instead I can just keep the source JSON blob right next to my structured data in postgres.